Enhancing Coal Seam Gas Recovery Using GreenZyme™

Coal Seam Gas (CSG) Extraction: Enhancing Recovery with GreenZyme™

=======================================================

Coal Seam Gas (CSG) extraction faces persistent challenges. Low permeability and high water saturation in coal formations hinder efficient gas recovery. This study investigates the application of GreenZyme™ (GZ), a biodegradable enzyme-based surfactant, to improve gas recovery. By modifying fluid dynamics within coal seams, GZ offers a promising solution. Through core flooding experiments and reservoir simulations, the research demonstrates that GZ significantly enhances relative permeability and cumulative gas production. This provides a low-cost, environmentally friendly alternative to conventional stimulation techniques.

Coal core modeling and filtration test using GreenZyme

Experimental Design & Methodology

Two coal samples from the Sydney Basin were subjected to core flooding tests. We evaluated the impact of GZ on fluid displacement and permeability. The samples were saturated with either water or a GZ solution. Then, we flooded them with helium to simulate gas flow without the confounding effects of methane sorption. Relative permeability curves were derived using the JBN method. We also measured interfacial tension (IFT) across varying GZ concentrations. These lab results were then scaled using Eclipse reservoir simulation software to model field-scale production outcomes.

Key Findings in Coal Seam Gas

1. Interfacial Tension Reduction

GreenZyme™ reduced IFT from approximately 70 mN/m to 45 mN/m at a concentration of 1.2 wt%. This reduction facilitates more efficient water displacement and gas mobility within the coal matrix.

2. Improved Relative Permeability

• Gas permeability at residual water saturation increased from 0.4 to 0.7.

• Water permeability also improved, particularly in narrow fracture networks.

• Relative permeability curves shifted upward and leftward, indicating enhanced fluid flow dynamics.

  
  

3. Enhanced Water Displacement with GreenZyme

GZ-treated samples showed a ~5% increase in water removal. This improvement is critical for unlocking trapped methane and enhancing gas flow pathways.

4. Simulation Insights for Coal Seam Gas Well

• GZ-enhanced wells produced more water initially, clearing the coal seam.

• Gas production surpassed baseline wells after 0.29 years.

• Cumulative gas recovery was higher in the GZ scenario by 0.47 years, demonstrating long-term performance gains.

  
  

Mechanisms of Action of GreenZyme

GreenZyme™ operates through multiple synergistic mechanisms:

• IFT Reduction: Lowers capillary forces, enabling water to be displaced more easily.

• Wettability Alteration: Potential shift toward more water-wet conditions, improving gas flow.

• Fracture Network Optimization: GZ effects are most pronounced in complex, low-permeability fracture systems.

  
  

Field Deployment & Strategic Implications

GreenZyme™ offers a compelling operational profile:

• Biodegradable and Low-Toxicity: Aligns with ESG goals and regulatory standards.

• Simple Integration: Can be injected during routine well workovers or blended with fracturing fluids.

• Cost-Effective: Requires no continuous dosing and avoids the high costs of hydraulic fracturing or thermal stimulation.

  
  

For operators seeking to improve recovery rates while minimizing environmental impact and operational complexity, GZ represents a scalable, field-ready solution.

Permeability curve and the spread of GreenZyme over time.

Recommendations for Future Research with GreenZyme

To validate and extend these findings in Coal Seam Gas, the following steps are recommended:

• Conduct experiments using methane to account for sorption and matrix effects.

• Quantify GZ’s impact on wettability and capillary pressure.

• Optimize injection protocols for large-scale field deployment.

  
  

To read the full research paper, please use this link: https://doi.org/10.1016/j.coal.2025.104866.

For more on the Author Wen Xi, please connect with them here on Linkedin.

Conclusion

In conclusion, the application of GreenZyme™ in Coal Seam Gas extraction presents a transformative opportunity. By enhancing gas recovery through improved fluid dynamics, GZ not only addresses the challenges of low permeability and high water saturation but also aligns with environmental goals. As we move forward, further research and field trials will be essential to fully realize the potential of this innovative technology. The future of CSG extraction could be brighter with GreenZyme™ leading the way!